Climate Change and Sea Level Rise

According to studies conducted by the U.S. Geological Survey (USGS), “In the San Francisco-Monterey Bay region, relative sea-level is rising at 2.29 mm/yr.” They add that in contrast to the northern Pacific coast, the wave energy in this area is moderate to high, and decreases as you move down the coast to a low wave energy in southern California. This reflects data obtained from a project called the Coastal Vulnerability Index (CVI) which was developed to determine the physical response of the coastline to sea level rise. The USGS is documenting shoreline retreat, beach loss, cliff retreat, and land loss rates, which are critical to coastal zone planning and resource protection. Learn more at this link: http://pubs.usgs.gov/of/2000/of00-178/pages/intro.html

Based upon their research, USGS estimates that “sea-level rise will have a large, sustained impact on coastal evolution at the societally-important decadal time scale.”

What does this mean for the over 280 miles of California State Parks coastline? It could potentially spell the loss of cultural resources such as prehistoric village sites at many of the coastal parks, as well as threatening historic trails, roads, and structures.

Climatic change also has the potential to impact the State Parks’ 625 miles of lake and river frontage. Many of these park lands also have cultural as well as natural and recreational resources that may be threatened with changes in environmental regimes.

Through the study of archaeology, we know that there have been periodic climatic irregularities that have affected human populations in various ways in the past. Paleoclimatic and paleohydrologic data indicates that the period from AD 800 to 1350 was a time of drought and increased ambient temperatures referred to as the Medieval Climatic Anomaly (MCA). By studying archaeological sites dating to this period throughout the West, the effects of climate change on flora and fauna can be better understood, and may help us to anticipate some of the similar climatic changes related to global warming.

Extended warming periods, and their attendant drought conditions, such as the MCA, may draw lakes and rivers down to very low levels, something that would have major implications within California’s State Parks. Low water levels for Mono Lake during the MCA are indicated by relict tree stumps exposed by drawdown of the lake’s water during this time period. Reports of up to fifteen meters (49 feet) difference are recorded between the current water level and those of the period between roughly AD 1000 and 1400. According to Scott Stine of CSU Hayward’s Department of Geography and Environmental Studies, if this drought were to occur today given California’s population levels, the impacts would be “highly disruptive environmentally and economically.”

With anticipated climatic change there will be many things to consider. Planning for protection and preservation of California’s cultural and natural heritage in our parks will be a challenge for the Department of Parks and Recreation, but one in which we can seek some answers by looking into our past and learning from those who dealt with similar issues.